Hostname: page-component-cd9895bd7-lnqnp Total loading time: 0 Render date: 2024-12-25T15:42:13.105Z Has data issue: false hasContentIssue false
  • English
  • Français

Period-Luminosity-Metal Abundance Relations for Population II Variable Stars

Published online by Cambridge University Press:  15 February 2018

James M. Nemec  and
Thomas E. Lutz
James M. Nemec
Affiliation:
Astronomy Department, University of Washington, Seattle, WA 98195, USA Program in Astronomy, Washington State University, Pullman, WA 99164, USA
Thomas E. Lutz
Affiliation:
Program in Astronomy, Washington State University, Pullman, WA 99164, USA

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

New period-luminosity-metallicity (P-L-[Fe/H]) relationships for Pop. II Cepheids, RR Lyrae stars, anomalous Cepheids and SX Phe (variable-blue straggler) stars are presented. These were computed by fitting regression lines to observed pulsation periods and mean B, V, K magnitudes for over 1200 stars in ∼40 stellar systems. The stars were assumed to be pulsating in either the fundamental (F) or first-overtone (H) modes (excluding double-mode and other multi-periodic variables). Eight P-L-[Fe/H] relationships (one for each of the two pulsation modes for the four kinds of stars) were simultaneously fitted for each filter. After accounting for the metal abundance differences, the slopes of the P-L relations were tested for departures from equality. The results are consistent with the assumption that, for each kind of star, the relations for the F and H stars are vertically offset, with a family of lines corresponding to the different metallicities. In the case of the globular cluster Cepheids, the available B, V data support Arp's 1955 contention that the Cepheids are oscillating in the F and H modes; moreover, the majority of the short-period Cepheids (BL Her stars) appear to be first-overtone pulsators, while most of the Cepheids with periods between 10 and 30 days (W Vir stars) appear to be fundamental-mode pulsators. For the RR Lyrae stars, the slopes of the P-L-[Fe/H] relations in B, V and K show a clear trend with filter type, namely, the absolute values of the slopes increase from B to K. Finally, for the SX Phe stars the differences between the P-L-[Fe/H] relations in B and V for the F and H stars are found to be consistent with the known period-ratio for the double-mode star SX Phe.

Type
Variable Stars as Distance Indicators
Information
International Astronomical Union Colloquium , Volume 139: New Perspectives on Stellar Pulsation and Pulsating Variable Stars , 1993 , pp. 31 - 52
Copyright
Copyright © Cambridge University Press 1993

References

Antonello, E., Broglia, P., Conconi, P. & Mantegazza, L. 1986, A&A, 169, 122.Google Scholar
Arp, H.C. 1955, AJ, 60, 1.Google Scholar
Bohm-Vitense, E. 1988, ApJ, 324, L27.Google Scholar
Bohm-Vitense, E., Szkody, P., Wailerstein, G. & Iben, I. 1974, ApJ, 194, 125.Google Scholar
Buonanno, R., Corsi, C.E., Fusi Pecci, F. 1989, A&A, 216, 80.Google Scholar
Buonanno, R., Cacciari, C., Corsi, C.E., Fusi Pecci, F. 1990, A&A, preprint.Google Scholar
Cacciari, C. 1984, AJ, 89, 231.Google Scholar
Catelan, M. 1993, these proceedings, p.271.Google Scholar
Da Costa, G. 1988, In The Harlow Shapley Symposium on Globular Cluster Systems in Galaxies, IAUSymp 126, ed. Grindlay, J. & Philip, A.G.D., Dordrecht:Reidel, p.217.Google Scholar
Demers, S. & Harris, W.E. 1974, AJ, 79, 627.Google Scholar
Fahlman, G.G., Richer, H.B. and VandenBerg, D.A. 1985, ApJ, 58, 25.Google Scholar
Fernie, D. 1992, AJ, 103, 1647.Google Scholar
Goldsmith, C. 1993, these proceedings, p.347 Google Scholar
Harris, H.C. 1985, In Cepheids: Theory and Observations ed. Madore, B.F., Cambridge University Press, p.232.Google Scholar
Hodder, P.J.C., Nemec, J.M., Richer, H.B. & Fahlman, G.G. 1992, AJ, 103, 460.Google Scholar
Jorgensen, H. & Hansen, L. 1984, A&A, 133, 165.Google Scholar
Joy, A. H. 1949, ApJ, 110, 105.Google Scholar
Lawson, C. L. & Hanson, R. J. Solving Least Squares Problems (Prentice-Hall, Englewood Cliffs, New Jersey, 1974).Google Scholar
Lee, Y.-W. 1990, Ph.D. Thesis, Yale University.Google Scholar
Lee, Y.-W. 1993, these proceedings, pp. 285–294.Google Scholar
Lee, Y.-W., Demarque, P. & Zinn, R. 1990, ApJ, 350, 155.Google Scholar
Liu, T. & Janes, K.A. 1993, these proceedings, p. 28.Google Scholar
Longmore, A.J., Dixon, R., Skillen, L., Jameson, R. & Fernley, J. 1990, MNRAS, 247, 684.Google Scholar
Longmore, A.J. 1993, these proceedings, pp. 19–27.Google Scholar
Mateo, M., Harris, H., Nemec, J., Olszewski, E. & Schombert, J. 1988, BAAS, 20, 717.Google Scholar
Mateo, M., Harris, H.C., Nemec, J.M. & Olszewski, E. 1990, AJ, 100, 469.Google Scholar
Nemec, J. M. In The Use of Pulsating Stars in Fundamental Problems of Astronomy, IAU Coll 111, (ed. Schmidt, E.G.) pp. 215–245 (Cambridge University Press, 1989).Google Scholar
Nemec, J. M. & Mateo, M. 1990, ASP Conf.Ser. 11, 64.Google Scholar
Nemec, J.M., Wehlau, A. & Oliveira, C. 1988, AJ, 96, 528.Google Scholar
Petersen, J.O. 1993, A&A, preprint.Google Scholar
Pike, CD. & Meston, C.J. 1977, MNRAS, 180, 613.Google Scholar
Sandage, A.R. 1970, ApJ, 162, 841.Google Scholar
Sandage, A.R. & Katem, B. 1977, ApJ, 215, 62.CrossRefGoogle Scholar
Sandage, A.R. 1990, ApJ, 350, 603.Google Scholar
Sandage, A.R., Katem, B. & Sandage, M. 1981, ApJS, 46, 41.Google Scholar
Sawyer Hogg, H. 1973, PDDO, 3, 1.Google Scholar
Seber, G. A. F. 1977, Linear Regression Analysis, (Wiley, New York).Google Scholar
Simon, N. & Lee, A.S. 1981, ApJ, 248, 291.Google Scholar
Simon, N. & Clement, CM. 1993, these proceedings, pp. 304–312.Google Scholar
Smith, H.A., Silbermann, N.A., Baird, S.R. & Graham, J.A. 1992, AJ, 104, 1430.Google Scholar
Walker, A. & Mack, P. 1988, AJ 96, 1362.Google Scholar
Welch, D., Mateo, M., Olszewski, E., Fischer, P. & Takamiya, M. 1993, AJ, 105, 146.Google Scholar
Zinn, R. 1985a, Mem.S.A.It., 56, 223.Google Scholar
Zinn, R. 1985b, ApJ, 293, 424.Google Scholar
Zinn, R. & King, C.R. 1982, ApJ, 262, 700.Google Scholar
Zinn, R. & West, M.J. 1984, ApJS, 55, 45.Google Scholar